Fiji Sevens coach Ben Ryan has warned that Jarryd Hayne faces a battle to realise his Olympic dream as the island nation's rugby reaches a 'golden era' ahead of Rio.
NFL-convert Hayne was in the squad as Fiji claimed their second successive World Sevens Series crown on Saturday after booking their place in the London Sevens quarterfinals.
They might have gone off the boil ever so slightly by finishing fourth overall on Sunday -- losing to reigning London champions USA in the third place playoff -- but Ryan is convinced he has a squad capable of adding Olympic gold to their world title.
Whether or not Hayne is part of the squad in Rio will depend on his performances during a seven-week training camp and Ryan suggested the 28-year-old would have to work on his fitness before rugby returns to the Olympics in August.
"It's so hard [to switch to sevens]," Ryan said. "There's the amount of fitness you need, as well as coming into a new team and a new game. Unless you're coming from another planet, no one's going to suddenly come into this and be a world beater.
"Look at a world class player like [New Zealand's] Sonny Bill [Williams]. It's taken him nine months, he's had to strip down and learn the game. The runway is incredibly short for Jarryd in his aspirations for Rio."
Hayne's hop from American football to rugby sevens marked his second switch of sport in little over a year. The former San Francisco 49ers running back previously quit a lucrative career as a rugby league star in his native Australia for a shot at America's Game.
His decision to join up with Fiji Sevens, representing the country of his father's birth, rather than opt for a return to Australia caused a stir Down Under, but Ryan revealed he had been a welcome presence in the squad.
"Jarryd's been very humble when he's come in," Ryan said. "Obviously there's a media circus that surrounds him but he's gelled in well. You've got to give him a lot of credit. He didn't know any of the team beforehand, he doesn't speak Fijian, but he is obviously professional in his attitude and is very willing to learn."
Fiji were in London without six of their first-choice players, including Vatemo Ravouvou -- fourth on the list of top points-scorers this sevens season. Ravouvou's injury paved the way for Hayne to make his debut and Ryan admitted he had an embarrassment of riches at his disposal.
"It's the first time in Fiji's history that we've won back-to-back titles, only New Zealand have done it before," Ryan said. "It's a remarkable achievement in an Olympic year. For a small island nation to be dominating the abbreviated game, we're in a golden era of Fijian rugby.
"We've got a group now that are resilient, so under pressure they perform. In 10 tournaments this year we've been in nine semifinals or better. It's remarkable consistency. That's down to world class players and a group that are now looking forward to a few games in South America in a couple of months."
"I hope the celebrations will be a bit more muted on the Island, but I'm probably banging my head against a wall in that respect. We'll give the boys two weeks off, then we're into camp, where we're going to have a shoot-out between 24 players. Seven weeks and by the end of it we'll have 12 players. Our cupboard is not just deep, it's absolutely littered with fantastic talent."